It becomes very hot. As per my initial use it use somewhere between 60-70C but I've read someone measure it as high as 81C. I purchased a 1mm copper heatsink with thermal tape and attached it to this SSD. As per my measurement temperatures range from 34C to 46C. I've read somewhere 50C is still considered normal or acceptable. Note not purchase the 3mm heatsinks (the ones with fins) as they are designed for desktops. The 1mm copper heatsink fits perfectly on ,y HP Pavilion gaming laptop replacing the meatl bracket (with thermal paste) holding the old SSD.